Isolation, Identification and Role of Glyphosate-Degrading Bacteria from Soils of Baghdad

Abstract

Glyphosate(N-phosphonomethylglycine) is the most commonly used herbicide worldwide. Dueto concern regarding its toxicity for non-targeted species in soil, findingglyphosate-degrading microorganisms in soil is important as these bacteria cangrow by utilizing glyphosate as a source of carbon. Two bacteria species wereisolated from soils of Baghdad. Morphological characteristic and biochemicalreactions indicated these species were identified as Bacillus and Serratiamarcescens. These bacterial isolates showed an ability to consume glyphosate asenergy and sole carbon source at 20 mM. The growth of bacteria in the mediacontaining glyphosate was determined after two days of incubation at 30 C bymeasuring turbidity (O.D) at 680 nm. The maximum growth of Bacillus inhalogenated compound containing media was found to be (O.D=0.3836) after twodays of incubation as compared to control media (O.D=0.0170)  withouthalogenated compound. In comparison to Bacillus, Serratia marcescensshowed less growth activity (O.D=0.06) in halogenated compound containing mediaafter two days of incubation as compared to its growth in control media (O.D=0.03). The maximum chloride ion released due to dehalogenase enzymeactivity was higher for Bacillus (O.D=1.3199) as compared to S.marcescens (O.D= 0.3) with respect to their control media (O.D =0.0491 and0.04) respectively. This result gives hint regarding the role of dehalogenasepresent in the bacteria for their affinity to substrate and utilizing it fortheir growth. For a better understanding of dehalogenase enzyme produced bythese two bacterial species, more research has to be explored for theirpossible use as bioremediation tools in the natural environment.